Herbicides



United States Patent 280, 8 Claims. (Cl. 260-2943) This invention relates to new and novel compounds particularly useful as herbicides.

This case is a continuation-in-part of my copending US. patent application Ser. No. 294,726, filed June 12, 1963.

Many herbicidal compounds are known of varying effectiveness. One of the difficulties however, with the practical use of most of the known herbicidal compounds lies in the fact that their herbicidal activities are not sufliciently specific. Thus in agricultural practice there are few herbicidal compounds that may be satisfactorily employed as most of the known herbicidal agents damage the desired crop to the same extent as they damage the undesired weeds.

A principal object of my invention, therefore, is to provide new and novel herbicidal compounds.

Another object of my invention is to provide new and novel herbicidal compounds that are selective in their herbicidal activities.

These and other objects of my invention will be apparent from the description that follows.

According to my invention I have prepared novel halogenated thiobenzamide compounds of the formula:

wherein X is a member selected from the group consisting of hydroxy, alkoxy of 1 to carbon atoms, the group wherein R and R each represent alkyl of l to 5 carbon atoms and N together with R and R represent pyridyl and pyrryl.

These novel chlorinated thiobenzarnides of my invention have useful herbicidal activities and may be employed to destroy not only young plants but also undesired older weed plants. Further, the novel compounds of my invention may be used in pre-emergent as well as postemergent applications.

The compounds of my invention may be prepared according to methods known for the preparation of such similar compounds or by methods analogous thereto.

The thiobenzamides of my invention wherein X represents an alkoxy group, may be prepared, for example, by causing a compound of the formula:

01 s fi N-CHz-Y 01 in which Y represents a halogen atom, preferably a chlorine atom, or a hydroxy group, to react with an alcohol having 1 to 5 carbon atoms and an alkyl halide respectively, preferably an alkylchloride, having 1 to 5 carbon 3,419,567. Patented Dec. 31, 1968 ice atoms, possibly in the presence of metallic sodium or a halogen binder, for example, silver ions.

The compounds of my invention, wherein X represents a group, may be prepared, for example, by causing a compound of the Formula 2 to react with an amine of the formula in which formula R and R represent an alkyl group having 1 to 5 carbon atoms or, together a saturated or unsaturated alkylene group having 4 to 5 carbon atoms.

In the case that R R and N together constitute a pyridine ring, the compounds of my invention can be prepared by causing a compound of Formula 2, in which Y is a halogen atom, preferably a chlorine atom, to react with pyridine.

The novel thiobenzamides of my invention wherein X is hydroxyl may be prepared by reacting a corresponding acid chloride with hexamethylene tetramine or by the simultaneous action of ammonia and formaldehyde or paraformaldehyde on a corresponding acid chloride. These novel compounds of my invention, however (wherein X is hydroxy), are preferably prepared by reacting a suitable dichlorothiobenzamide with formaldehyde or paraformaldehyde and especially with formalin.

The preparation and methods of employing the novel compounds of my invention will now be explained in greater detail with reference to the following examples:

Example 1 A mixture of 175 g. of 2,6-dichlorothiobenzamide, 1 litre of 36% by weight of formalin, 500 cc. of dioxane and cc. of 2 N solution of caustic soda was stirred at room temperature for 2 hours. The resulting solution was homogeneous. The homogeneous mixture was poured in 2 litres of an aqueous solution of common salt. The precipitated oil was extracted four times with 250 cc. of ether. The collected extracts were washed with 600 cc. of a 2 N solution of caustic soda and then with water. After condensation by evaporation to about 500 cc. the ethereal solution was washed four times with 75 cc. of 2 N solution of caustic soda.

The collected caustic soda extracts were washed with 150 cc. of ether, after which the ether was removed by evaporation under reduced pressure at from 20 C. to 25 C. and the condensate was cooled to 10 C. After filtration, 200 cc. of concentrated hydrochloric acid were added while stirring. The resulting mixture was stirred for one hour at a temperature of from 15 C. to 20 C. and then allowed to stand. After standing 15 hours the precipitated oil had entirely solidified; the solid substance was drawn off, washed with water several times and dried. The yield of N-hydroxymethyl-Z,6-dichlorothiobenzamide was 163 g. (81% of the theoretical yield). Melting point 112 C.115 C.

Example 2.-N-methoxyrnethyl-2,6-dichlorothiobenzamide 5.08 grams of N-chloromethyl-Z,fi -dichlorothiobenzamide (prepared from N-hydroxymethyl-Z,fi-dichlorothiobenzamide by means of PCI were suspended in 20 ml. of acetone.

3.06 grams of pulverized silver nitrate and 30 ml. of methanol were simultaneously added to this suspension 3 within 5 to 10 minutes while stirring, the temperature being maintained at 20-25 C. Then the mixture was stirred for another 15 minutes and then poured on 2.1 g. of soda. The pH had become 7. The solvent was distilled off for the greater part. The residue was cooled 4 with concentrated hydrochloric acid while stirring an cooling in ice water. The precipitate was vacuum filtered off and crystallized from approximately 20 ml. of a mixture of 1 part of benzene and 2 parts of petroleum ether 40-60. Yield: 3.0 g. Melting range: lll22 C.

o to 0 C. and the crystallized substance was filtered olf. The crystals were extracted with benzene. After the Examp 1e ggggggfg dlchloro benzene solution had been evaporated to ml., a solid i was precipitated by adding petroleum ether. Yield: 1.83 g. 25 h of methanol Whlch 9 P h Melting range: 133-139 C. After one crystallization 10 bqenhlssolvefl, were added t 20 i from isopropanol the melting range was within minutes to a solution of 8.9 g. of N-chloromethyl-2.6-dichlorothio'benzamide in 30 ml. of acetone. Example F After 75 minutes the reaction mixture was diluted with benzamlde 150 ml. of diethylether. The solution was washed with 118.0 g. of N-hydroxymethyl 2,6 dichlorothiobenz- 15 dilute acetic acid to weakly acid. Then the solution was amide were of dry benzene extracted 5 times, each of 2 N sodium f thionylchloride were added dropwise hi i i hydroxide. The combined alkaline extracts were purified within 15 minutes. The clear benzene solution was heated With active carbon at room temperature- The mixture was to boiling on the Water bath f 15 i Aft h filtered and the filtrate was carefully acidified with hydroing cooled the reaction mixture to C, 5 1 f 20 chloric acid to P11 2 to 3 while cooling in an ice bath. absolute ethanol were added in 5 minutes. Then stirring The crystallized Product was isolated and dried in was continued at room temperature for another 30 Yield? Melting range! 138-14? mlnutes- Example 7.'N-(dimethylaminomethyl)-2,6-dichlorolThe dsolutiorrvlzas1 filtielred, egaporggad 11H vatguo to 200 thiobenzamide o 1 fig gg i z gi gi z g g 56 31 of 20.6 g. of 2.6-dichlorothiobenzamide were stirred at 2 N KOH after which the alkaline solution was acidified a temperature 20 a mixture of 20 with concentrated hydrochloric acid, while cooling. The dlmethylemine solutlon 10 of 40% formahne crystalline product formed was filtered off and dried in air. and 125 f dloxane' After i mlxture been left Yield: 51 Melting point 1144150 0 to stand at 20 C. for 15 hours, it was poured nto water. The resultant precipitate was filtered off and dried. Yield: Example 4.N-n-pr;poxyn iethyl-2,6-dichloroth1o- 25 g, Melting point 147 149 C enzamlde Example 8.N-(pyridiniummethyl)-2,6-dichloro- 14.2 g.dof lgl-hsygrolxyrrfiihyll6-dichlgiiothio'biniamidf thio'benzamide hl i was mixe W1 m o ryenzene. m. o t ion chloride were added dropwise to this mixture in 5 minutes. g of Nihydroxymethyl'ze'dlchlomthloeenzemlde The resulting solution was then boiled under reflux for were mlxed Wlth 100 i of P i To thls h 15 minutes, cooled to 100 and diluted wtih 20 mL of there were added dropwise while stirring, and within 10 n-propanol. After 15 hours the solution was washed once m of thlonylehlonde' The benzene $0111 with water and then 10 times with totally 500 ml. of 40 Was.heate(.1on the Water bath for 15 t After 2 N potassium hydroxide solution. The extracts were ft mlxture had been cooled to 10 15 of combined, treated with carbon and carefully neutralized Pyndme e with concentrated hydrochloric acid while stirring and The resultmg 'preelpltete Sucked and dned m cooling in ice water. The precipitate was filtered off and vaeuo' Yleld: 30 pemt crystallized from a mixture of 1 part of benzene and The compounds aeeoremg to e mventlon a a 2 parts of petroleum ether 4040 Yield: 25 g Melting strong pre-emergence action on various WCCdS. Th1S acrange: 7785 C. After recrystallization from ethanol/ 15 shown In the followmg expenfnent m Whleh water 1:2 Me1tingpOint88 91 0 seeds of various weeds were sprayed with an aqueous solution or suspension of one of the compounds. After Exal'hP1e QP P h Y a few days the percentage of the seeds that had not thlobehzamlde germinated was determined. In Table I the results of 14.2 g. of N-hydroxymet-hyl-Z,6-dichlorothiobenzamide experiment are given in which the seeds Were treated were mixed with ml. of dry benzene. 5.1 ml. of thionyl- Wlth a quahtlty of Substance the following formula, chloride were added dropwise to this mixture in 5 minutes. Which, in Practice, cormspohds 10 kg/ha- The resulting solution was boiled under reflux for 15 55 01 minutes, cooled to 10 C. and diluted with 20 ml. of S isopropanol. After 15 hours the solution was washed once with water and then 5 times with 20 ml. of 2 N potassium hydroxide solution. The extracts were com- 01 bined, treated with carbon and then carefully neutralized H TABLE I White Annual X mustard meadow Ohiekweed Cress Millet Wild oats grass N(cH3 i.

00113 :l: OC2H5 .4 i O(CHz)2CHa OCH CH3 2 means inhibition of the seed germination. means s0-i00% inhibition of the seed germination. :1; means 10-80% inhibition of the seed germination.

It has been found in post-emergence experiments that the compounds according to the invention also have an interesting action on young and fullgrown plants. With some compounds of my invention weeds in vegetation can be killed without the vegetation being damaged noteworthily.

The compound of Formula 1, in which X represents an isopropoxy group and n=0, has been found to be suitable for killing nettles in dwarf French bean.

The post-emergence action is shown in the-following experiment in which various seeds and vegetation were sprayed with a solution or suspension of compounds of my invention in acetone in a quantity corresponding to 10 kg./ha. After some time the damage done tothe plants was estimated and evaluated with a cipher from t0 6, these ciphers having the following meanings:

0=no damage 1=up to 35 part of the leaves burned 2=% /a part of the leaves burned /3% part of 'the leaves burned 4=%-% part of the leaves burned 5=% part of the leaves or more burned 6=plant died sired mixed with aromatic hydrocarbons, for example toluene and xylene.

A dispersion may be produced by pouring into water a miscible oil which, for example, is produced by mixing parts by weight of active ingredient, 10 parts by weight of polyoxyethylenesorbitan fatty acid ester, 25 parts by weight of acetone and parts by weight of methyl-ethyL ketone. 1;

While I have described my invention in connection with specific embodiments and applications, other modifications thereof will be readily apparent to those skilled in this art without departing from the spirit and scope of the invention as defined in the appended claims.

What I claim is:

1. A compound of the formula:

OCH; 0 2 2 062115 3 2 3 O (CHz)zCHs 3 2 4 OCH(CH3): 1 2 2 The compound N-hydroxymethyl-Z,6-dichlorothiobenzamide was found to be particularly useful in that it was able to destroy dicolyledonous weeds in wheat and barley without harming these cereal crops. Thus this compound can be used in the early spring to act as a pre-emergent weed killer for winter wheat.

The production of a herbicidal compositionglin accordance with the invention may be effected in manners known for such compositions. For example, an active substance may be mixed with a powdered inert carrier, such asjchalk, dolomite, kaolin, china clay or attapulgite or dissolved or dispersed in an inert solvent, such as toluene: xylene, aliphatic, alicyclic or aromatic ketones, for example acetone, methylethyl ketone or cyclohexanone, or mixtures thereof with hydrocarbons, if desired with the addition of surface-active substances and dispersion agents. It may also be mixed with artificial manures.

A dust may be produced by mixing 5 parts by weight of an active ingredient with 95 parts by weight of kieselguhr and grinding the mixture.

A Wettable powder may be produced by intimately mixing 20 parts by weight of an active ingredient with 5 parts by weight of oleyl-amidomethyltaurate, 10 parts by weight of calciumlignin sulphonate and 65 parts by weight of chalk and grinding the resulting mixture.

Miscible oils containing from 5-30% and preferably from 10-20% of active ingredient and from 5-10% of ionogenic or non-ionogenic emulsifying agents or mixtures thereof may be produced by dissolving these ingredients in organic solvents, for example, aliphatic or aromatic ketones, such as acetone and cyclohexanone, if dewherein X is a member selected from the group consisting of hydroxy, alkoxy of 1 to 5 carbon atoms,-L the group R: wherein R and R is each alkyl of 1 to 5 carbon atoms and R R together with N is pyrryl and pyridiniurn chloride.

2. N-methoxymethyl-2,6-dichlorothiobenzamide. 3. N-ethoxymethyl-2,fi-dichlorothiobenzamiile. 4. N-n-propoxymethyl-2,6-diehlorothiobenzamide. 5. N-isopropoxymeth yl-2,6-dichlorothioherizamide. 6. N-(dimethylaminornethyl) 2,6 dichlorothiobenzamide.

7. N-(pyridiniummethyl) 2,6-dichlorothiobenzamidechloride.

8. N-hydroxymethyl-2,6-dichlorothiobenzamide.

References Cited UNITED STATES PATENTS 2,201,170 5/ 1940 Hanford 260551 2,277,821 3/ 1942 Ericks 26055 1 2,744,819 5/1956 Toorman 71--2.6 2,829,038 4/ 1958 Ochsner 71-2.6 2,936,323 5/ 1960 Eden 71--2.6 2,577,969 12/1951 Jones 71-2.6

HENRY R. JILES, Primary Examiner.

H. I. MOATZ, Assistant Examiner.

U.S. Cl. X.R.

Patent No. 3,419,567 December 31, 1968 Johannes Wijma ror appears in the above identified It is certified that er eby corrected as patent and that said Letters Patent are her shown below:

Column 2, line 71, "3. 06" should read 3.6

signed and sealed this 14th day of April 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

1. A COMPOUND OF THE FORMULA: 